/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.graphics.spritetext;

import android.opengl.Matrix;

import javax.microedition.khronos.opengles.GL10;

/**
 * A utility that projects
 * 
 */
class Projector {
	public Projector() {
		mMVP = new float[16];
		mV = new float[4];
		mGrabber = new MatrixGrabber();
	}

	public void setCurrentView(int x, int y, int width, int height) {
		mX = x;
		mY = y;
		mViewWidth = width;
		mViewHeight = height;
	}

	public void project(float[] obj, int objOffset, float[] win, int winOffset) {
		if (!mMVPComputed) {
			Matrix.multiplyMM(mMVP, 0, mGrabber.mProjection, 0,
					mGrabber.mModelView, 0);
			mMVPComputed = true;
		}

		Matrix.multiplyMV(mV, 0, mMVP, 0, obj, objOffset);

		float rw = 1.0f / mV[3];

		win[winOffset] = mX + mViewWidth * (mV[0] * rw + 1.0f) * 0.5f;
		win[winOffset + 1] = mY + mViewHeight * (mV[1] * rw + 1.0f) * 0.5f;
		win[winOffset + 2] = (mV[2] * rw + 1.0f) * 0.5f;
	}

	/**
	 * Get the current projection matrix. Has the side-effect of setting current
	 * matrix mode to GL_PROJECTION
	 * 
	 * @param gl
	 */
	public void getCurrentProjection(GL10 gl) {
		mGrabber.getCurrentProjection(gl);
		mMVPComputed = false;
	}

	/**
	 * Get the current model view matrix. Has the side-effect of setting current
	 * matrix mode to GL_MODELVIEW
	 * 
	 * @param gl
	 */
	public void getCurrentModelView(GL10 gl) {
		mGrabber.getCurrentModelView(gl);
		mMVPComputed = false;
	}

	private MatrixGrabber mGrabber;
	private boolean mMVPComputed;
	private float[] mMVP;
	private float[] mV;
	private int mX;
	private int mY;
	private int mViewWidth;
	private int mViewHeight;
}
